Essai cinique randomisé / Objectifs : Démontrer la supériorité de l’analgésie périopératoire optimale par rapport aux traitements analgésiques usuels ou conventionnels pour diminuer l'intensité de la douleur aiguë postopératoire (DAPO), la fréquence d'apparition de la douleur chronique post chirurgicale (DCPC) et améliorer la qualité de vie des patients. Méthodes : Un essai clinique randomisé à double insu, sur 57 patients ayant subi une trapéziectomie à l'hôpital Notre-Dame du CHUM. Après avoir reçu une analgésie locorégionale via un cathéter du plexus brachial, le groupe expérimental a reçu une perfusion de bupivacaïne 0,5%, débutée dans la salle de réveil et poursuivie pendant 72 h en ambulatoire, grâce à une pompe à perfusion. Le groupe de contrôle a reçu une solution saline. Les deux groupes ont reçu du célécoxib durant cette même période. L'évolution du profil de la douleur, du fonctionnement de la main et de la qualité de vie des patients ont été saisis à l'aide de questionnaires et de tests fonctionnels en préopératoire et pendant six mois de suivi. Les résultats ont été analysés à l'aide du modèle linéaire général. Une différence de 2 au niveau de l'intensité de la douleur, mesurée par l'échelle visuelle analogique (EVA : 0-10), a été considérée statistiquement significative. Résultats : Notre méthode a abouti à une diminution significative de l'intensité de la DAPO et de la douleur chronique (DC) par rapport à la méthode conventionnelle. Les activités générales, la qualité du sommeil et la concentration des patients étaient significativement meilleures chez le groupe qui a reçu la nouvelle méthode. De plus, dans ce groupe il y avait deux fois moins des patients qui ont continué à souffrir de DC que le groupe de contrôle. Conclusion : Dans la chirurgie de la main, une couverture analgésique périopératoire est essentielle pour réduire l’intensité de la DAPO, la fréquence de la DCPC et pour améliorer la qualité de vie des patients. Mots-clés : essai clinique, douleur chronique, chirurgie, main, analgésie préventive, plexus brachial. / Objectives: Demonstrate the superiority of Optimal Perioperative Analgesia compared to Usual Analgesic Treatment to reduce the intensity of Acute Postoperative Pain (APOP), the frequency of occurrence of Chronic Post Surgical Pain (CPSP) and improve patients’ quality of life. Methods: A double-blinded randomized clinical trial conducted in Notre-Dame Hospital on 57 patients who underwent a trapeziectomy. After locoregional analgesia via a catheter in the brachial plexus, the experimental group received an infusion of bupivacaine 0.5%, which started in the recovery room and continued for 72 h as an outpatient through an infusion pump. Meanwhile, the control group received a saline solution. Both groups took celecoxib during the same period. The evolution of pain profile, hand function and patients’ quality of life have been obtained using questionnaires and functional tests in the preoperative period and through months of follow-up. Results were analyzed using General Linear Model. A difference of 2 in the intensity of pain, measured by Visual Analogue Scale (VAS: 0-10), was considered statistically significant. Results: This method resulted in a significant decrease in the intensity of APOP and Chronic Pain (CP) compared to usual treatment. General activities, quality of sleep and patients’ concentration were better in the experimental group. Moreover, two times less patients continued to suffer from the CP than in the placebo group. Conclusion: In hand surgery, a perioperative analgesic coverage is necessary to reduce the APOP intensity, the CPSP frequency and to improve patients’ quality of life. Keywords: clinical trial, chronic pain, surgery, hand, preemptive analgesia, brachial plexus.

O desenvolvimento de um método eficiente de avaliação prognóstica precoce seria de grande utilidade na seleção de lactentes com plexopatia braquial obstétrica para cirurgias de reconstrução do plexo braquial. Realizamos uma eletroneurografia bilateral em 33 bebês com plexopatia braquial obstétrica entre 10 e 60 dias de vida. Foram avaliadas e comparadas lado a lado as amplitudes dos potenciais de ação musculares compostos dos nervos axilar, musculocutâneo, radial proximal, radial distal, mediano e ulnar. Os bebês foram seguidos clinicamente até os seis meses de vida, quando foram submetidos a uma avaliação da força de vários grupos musculares e a uma prova funcional. Uma redução da amplitude do potencial de ação muscular composto em qualquer nervo do membro acometido maior ou igual a 90% da amplitude do potencial do membro sadio correlacionou-se com um resultado clínico ruim aos seis meses de idade (p < 0,01). A acurácia prognóstica da eletroneurografia foi de 91% para as lesões do tronco superior, 97% para as lesões do tronco médio e 100% para as lesões do tronco inferior. Nossos resultados indicam que a eletroneurografia parece ser um instrumento útil na avaliação prognóstica precoce de pacientes com plexopatia braquial obstétrica / Early prognostic assessment of obstetric brachial plexopathies would be a major step for rational selection of infants for brachial plexus surgery. We performed bilateral electroneurography of Axillary, Musculocutaneous, proximal Radial, distal Radial, Median and Ulnar nerves in 33 babies (age 10 - 60 days) with obstetrical brachial plexus lesions in order to compare the amplitude of compound muscle action potentials (CMAPs). The babies were followed up for six months and the outcome was classified according to muscle power score and functional performance. A CMAP amplitude reduction in any nerve of the injured side superior or equal to 90% of CMAP amplitude of the normal side was related to an unfavorable clinical result at age of six months (p < 0,01). The prognostic accuracy of electroneurography was 91% for the upper trunk, 97% for the middle trunk and 100% for the lower trunk. Our results indicate that electroneurography seems to be a useful tool for very early prognostic assessment of obstetric brachial plexopathies

INTRODUÇÃO: Estenose do canal cervical consiste na diminuição do diâmetro sagital do canal cervical e está associada com maior risco de lesões neurológicas decorrentes de trauma cervical. Nos esportes de colisão, a estenose do canal cervical consiste em um importante parâmetro na decisão de retorno ao esporte após neuropraxia da medula cervical e após determinadas lesões do plexo braquial. Os métodos atualmente disponíveis para avaliação de estenose do canal cervical em atletas são muito caros (ex: por ressonância nuclear magnética) ou pouco precisos (métodos radiográficos). Este estudo avaliou um novo método radiográfico para determinação de estenose do canal cervical, comparando-o com medições realizadas em cadáveres, medida por ressonância nuclear magnética do canal cervical e do espaço disponível para a medula (SAC/SACD) e com o método radiográfico consagrado na literatura para determinação de estenose do canal cervical, o índice de Torg (IT). MÉTODOS: A população do estudo foram 20 homens entre 16 e 35 anos de idade. Os sujeitos realizaram uma ressonância nuclear magnética da coluna cervical para determinação do SAC/SACD e radiografias cervicais em perfil e antero-posterior para determinação do IT e do novo método radiográfico proposto, o diâmetro corrigido do canal cervical (DCCC). Para determinar o DCCC, foi utilizada uma barra de metal de 100 mm, acoplada verticalmente na linha média cervical, utilizando os processos espinhosos das vertebras cervicais como referência. Obtidos o diâmetro sagital da imagem do canal cervical e o comprimento da imagem da barra de metal na radiografia, e conhecendo o tamanho real da barra de metal, o diâmetro real do canal medular pôde ser estimado matematicamente com o uso do teorema de Tales. Os resultados obtidos para o DCCC foram comparados com valores encontrados em estudos com cadáveres, foi avaliada a concordância entre DCCC e o diâmetro médio-sagital do canal cervical aferido por ressonância magnética (DCRM) e os métodos radiográficos (DCCC e IT) foram correlacionados com o SAC/SACD. Os cálculos foram realizados nos níveis C3 a C7, além das médias de C3 a C6 [DCCC (MDCCC), IT (MTorg) e SAC/SACD (MSAC/MSACD)]. RESULTADOS: Os valores obtidos pelo DCCC (média do MDCCC: 15.29 mm) foram compatíveis com os valores descritos em estudos de medida direta. A correlação entre DCCC e SAC/SACD foi superior à correlação entre IT e SAC/SACD, sendo de 0.7025 para MDCCC e MSACD contra 0.5473 para MTorg e MSACD. O teste de concordância entre os valores absolutos para DCCC e DCRM evidenciou valores mais elevados na medida por DCCC, sendo média de 1.84 mm maior para MDCCC em relação a média de C3 a C6 pelo DCRM. CONCLUSÕES: O Diâmetro Corrigido do Canal Cervical apresentou valores semelhantes aos encontrados em estudos com medida direta em cadáveres e apresentou correlação com SAC/SACD superior ao IT / INTRODUCTION: Cervical spinal stenosis is the diminution of the anteroposterior diameter of the spinal canal and it is associated with increased risk of neurological injury from cervical trauma. In collision sports, the cervical canal stenosis is an important parameter in the return to play decision after cervical cord neuropraxia and after some brachial plexus injuries. The methods currently available for evaluation of cervical canal stenosis in athletes are expensive (eg, nuclear magnetic resonance) or imprecise (radiographic methods). This study evaluated a new radiographic method for determination of cervical canal stenosis, comparing it to measurements performed on cadavers, measurement by magnetic resonance imaging of the cervical canal and space available for the cord (SAC/SACD) and the consecrated radiographic method for determining cervical spinal stenosis, Torg ratio(TI). METHODS: The study population were 20 men between 16 and 35 years. The subjects underwent a magnetic resonance imaging of the cervical spine to determine the SAC/SACD and cervical radiographs to determine the IT and the proposed new radiographic method, called corrected cervical canal diameter (DCCC). To determine the DCCC, a 100 mm metal bar was used vertically over the cervical midline, using the spinous processes of the cervical vertebrae as reference. Got the radiographic diameter of the medullary canal and the length of the metal bar image on the radiograph , and knowing the actual size of the metal bar , the actual diameter of the spinal canal could be estimated mathematically with the simple use of the theorem of Thales. The results for the DCCC were compared with values found in cadavers studies, the agreement between DCCC and the mid-sagittal diameter of the cervical canal measured by magnetic resonance imaging (DCRM) was calculated and radiographic methods (DCCC and IT) were correlated with SAC/SACD. Calculations were performed individually for C3 to C7 and averages of C3 to C6 [DCCC (MDCCC), IT (MTorg) and SAC/SACD (MSAC/ MSACD)]. RESULTS: The values obtained by DCCC (average MDCCC: 15:29 mm) were consistent with the values described in studies using direct measurement. The correlation between DCCC and SAC/SACD was higher than the correlation between IT and SAC/SACD, being 0.7025 for MDCCC and MSACD and 0.5473 for MTorg and MSACD. The agreement between absolute values for DCCC and DCRM showed higher values for DCCC, which average 1.84 mm greater for MDCCC compared to the average of C3 to C6 for DCRM. CONCLUSIONS: The Fixed Diameter of the Cervical Canal showed similar values to those found in studies with direct measurement from cadavers and correlated with SAC/SACD better than IT

Objectifs : Démontrer la supériorité de l’analgésie périopératoire optimale par rapport aux traitements analgésiques usuels ou conventionnels pour diminuer l'intensité de la douleur aiguë postopératoire (DAPO), la fréquence d'apparition de la douleur chronique post chirurgicale (DCPC) et améliorer la qualité de vie des patients. Méthodes : Un essai clinique randomisé à double insu, sur 57 patients ayant subi une trapéziectomie à l'hôpital Notre-Dame du CHUM. Après avoir reçu une analgésie locorégionale via un cathéter du plexus brachial, le groupe expérimental a reçu une perfusion de bupivacaïne 0,5%, débutée dans la salle de réveil et poursuivie pendant 72 h en ambulatoire, grâce à une pompe à perfusion. Le groupe de contrôle a reçu une solution saline. Les deux groupes ont reçu du célécoxib durant cette même période. L'évolution du profil de la douleur, du fonctionnement de la main et de la qualité de vie des patients ont été saisis à l'aide de questionnaires et de tests fonctionnels en préopératoire et pendant six mois de suivi. Les résultats ont été analysés à l'aide du modèle linéaire général. Une différence de 2 au niveau de l'intensité de la douleur, mesurée par l'échelle visuelle analogique (EVA : 0-10), a été considérée statistiquement significative. Résultats : Notre méthode a abouti à une diminution significative de l'intensité de la DAPO et de la douleur chronique (DC) par rapport à la méthode conventionnelle. Les activités générales, la qualité du sommeil et la concentration des patients étaient significativement meilleures chez le groupe qui a reçu la nouvelle méthode. De plus, dans ce groupe il y avait deux fois moins des patients qui ont continué à souffrir de DC que le groupe de contrôle. Conclusion : Dans la chirurgie de la main, une couverture analgésique périopératoire est essentielle pour réduire l’intensité de la DAPO, la fréquence de la DCPC et pour améliorer la qualité de vie des patients. Mots-clés : essai clinique, douleur chronique, chirurgie, main, analgésie préventive, plexus brachial. / Objectives: Demonstrate the superiority of Optimal Perioperative Analgesia compared to Usual Analgesic Treatment to reduce the intensity of Acute Postoperative Pain (APOP), the frequency of occurrence of Chronic Post Surgical Pain (CPSP) and improve patients’ quality of life. Methods: A double-blinded randomized clinical trial conducted in Notre-Dame Hospital on 57 patients who underwent a trapeziectomy. After locoregional analgesia via a catheter in the brachial plexus, the experimental group received an infusion of bupivacaine 0.5%, which started in the recovery room and continued for 72 h as an outpatient through an infusion pump. Meanwhile, the control group received a saline solution. Both groups took celecoxib during the same period. The evolution of pain profile, hand function and patients’ quality of life have been obtained using questionnaires and functional tests in the preoperative period and through months of follow-up. Results were analyzed using General Linear Model. A difference of 2 in the intensity of pain, measured by Visual Analogue Scale (VAS: 0-10), was considered statistically significant. Results: This method resulted in a significant decrease in the intensity of APOP and Chronic Pain (CP) compared to usual treatment. General activities, quality of sleep and patients’ concentration were better in the experimental group. Moreover, two times less patients continued to suffer from the CP than in the placebo group. Conclusion: In hand surgery, a perioperative analgesic coverage is necessary to reduce the APOP intensity, the CPSP frequency and to improve patients’ quality of life. Keywords: clinical trial, chronic pain, surgery, hand, preemptive analgesia, brachial plexus. / Essai cinique randomisé

INTRODUÇÃO: Estenose do canal cervical consiste na diminuição do diâmetro sagital do canal cervical e está associada com maior risco de lesões neurológicas decorrentes de trauma cervical. Nos esportes de colisão, a estenose do canal cervical consiste em um importante parâmetro na decisão de retorno ao esporte após neuropraxia da medula cervical e após determinadas lesões do plexo braquial. Os métodos atualmente disponíveis para avaliação de estenose do canal cervical em atletas são muito caros (ex: por ressonância nuclear magnética) ou pouco precisos (métodos radiográficos). Este estudo avaliou um novo método radiográfico para determinação de estenose do canal cervical, comparando-o com medições realizadas em cadáveres, medida por ressonância nuclear magnética do canal cervical e do espaço disponível para a medula (SAC/SACD) e com o método radiográfico consagrado na literatura para determinação de estenose do canal cervical, o índice de Torg (IT). MÉTODOS: A população do estudo foram 20 homens entre 16 e 35 anos de idade. Os sujeitos realizaram uma ressonância nuclear magnética da coluna cervical para determinação do SAC/SACD e radiografias cervicais em perfil e antero-posterior para determinação do IT e do novo método radiográfico proposto, o diâmetro corrigido do canal cervical (DCCC). Para determinar o DCCC, foi utilizada uma barra de metal de 100 mm, acoplada verticalmente na linha média cervical, utilizando os processos espinhosos das vertebras cervicais como referência. Obtidos o diâmetro sagital da imagem do canal cervical e o comprimento da imagem da barra de metal na radiografia, e conhecendo o tamanho real da barra de metal, o diâmetro real do canal medular pôde ser estimado matematicamente com o uso do teorema de Tales. Os resultados obtidos para o DCCC foram comparados com valores encontrados em estudos com cadáveres, foi avaliada a concordância entre DCCC e o diâmetro médio-sagital do canal cervical aferido por ressonância magnética (DCRM) e os métodos radiográficos (DCCC e IT) foram correlacionados com o SAC/SACD. Os cálculos foram realizados nos níveis C3 a C7, além das médias de C3 a C6 [DCCC (MDCCC), IT (MTorg) e SAC/SACD (MSAC/MSACD)]. RESULTADOS: Os valores obtidos pelo DCCC (média do MDCCC: 15.29 mm) foram compatíveis com os valores descritos em estudos de medida direta. A correlação entre DCCC e SAC/SACD foi superior à correlação entre IT e SAC/SACD, sendo de 0.7025 para MDCCC e MSACD contra 0.5473 para MTorg e MSACD. O teste de concordância entre os valores absolutos para DCCC e DCRM evidenciou valores mais elevados na medida por DCCC, sendo média de 1.84 mm maior para MDCCC em relação a média de C3 a C6 pelo DCRM. CONCLUSÕES: O Diâmetro Corrigido do Canal Cervical apresentou valores semelhantes aos encontrados em estudos com medida direta em cadáveres e apresentou correlação com SAC/SACD superior ao IT / INTRODUCTION: Cervical spinal stenosis is the diminution of the anteroposterior diameter of the spinal canal and it is associated with increased risk of neurological injury from cervical trauma. In collision sports, the cervical canal stenosis is an important parameter in the return to play decision after cervical cord neuropraxia and after some brachial plexus injuries. The methods currently available for evaluation of cervical canal stenosis in athletes are expensive (eg, nuclear magnetic resonance) or imprecise (radiographic methods). This study evaluated a new radiographic method for determination of cervical canal stenosis, comparing it to measurements performed on cadavers, measurement by magnetic resonance imaging of the cervical canal and space available for the cord (SAC/SACD) and the consecrated radiographic method for determining cervical spinal stenosis, Torg ratio(TI). METHODS: The study population were 20 men between 16 and 35 years. The subjects underwent a magnetic resonance imaging of the cervical spine to determine the SAC/SACD and cervical radiographs to determine the IT and the proposed new radiographic method, called corrected cervical canal diameter (DCCC). To determine the DCCC, a 100 mm metal bar was used vertically over the cervical midline, using the spinous processes of the cervical vertebrae as reference. Got the radiographic diameter of the medullary canal and the length of the metal bar image on the radiograph , and knowing the actual size of the metal bar , the actual diameter of the spinal canal could be estimated mathematically with the simple use of the theorem of Thales. The results for the DCCC were compared with values found in cadavers studies, the agreement between DCCC and the mid-sagittal diameter of the cervical canal measured by magnetic resonance imaging (DCRM) was calculated and radiographic methods (DCCC and IT) were correlated with SAC/SACD. Calculations were performed individually for C3 to C7 and averages of C3 to C6 [DCCC (MDCCC), IT (MTorg) and SAC/SACD (MSAC/ MSACD)]. RESULTS: The values obtained by DCCC (average MDCCC: 15:29 mm) were consistent with the values described in studies using direct measurement. The correlation between DCCC and SAC/SACD was higher than the correlation between IT and SAC/SACD, being 0.7025 for MDCCC and MSACD and 0.5473 for MTorg and MSACD. The agreement between absolute values for DCCC and DCRM showed higher values for DCCC, which average 1.84 mm greater for MDCCC compared to the average of C3 to C6 for DCRM. CONCLUSIONS: The Fixed Diameter of the Cervical Canal showed similar values to those found in studies with direct measurement from cadavers and correlated with SAC/SACD better than IT

O desenvolvimento de um método eficiente de avaliação prognóstica precoce seria de grande utilidade na seleção de lactentes com plexopatia braquial obstétrica para cirurgias de reconstrução do plexo braquial. Realizamos uma eletroneurografia bilateral em 33 bebês com plexopatia braquial obstétrica entre 10 e 60 dias de vida. Foram avaliadas e comparadas lado a lado as amplitudes dos potenciais de ação musculares compostos dos nervos axilar, musculocutâneo, radial proximal, radial distal, mediano e ulnar. Os bebês foram seguidos clinicamente até os seis meses de vida, quando foram submetidos a uma avaliação da força de vários grupos musculares e a uma prova funcional. Uma redução da amplitude do potencial de ação muscular composto em qualquer nervo do membro acometido maior ou igual a 90% da amplitude do potencial do membro sadio correlacionou-se com um resultado clínico ruim aos seis meses de idade (p < 0,01). A acurácia prognóstica da eletroneurografia foi de 91% para as lesões do tronco superior, 97% para as lesões do tronco médio e 100% para as lesões do tronco inferior. Nossos resultados indicam que a eletroneurografia parece ser um instrumento útil na avaliação prognóstica precoce de pacientes com plexopatia braquial obstétrica / Early prognostic assessment of obstetric brachial plexopathies would be a major step for rational selection of infants for brachial plexus surgery. We performed bilateral electroneurography of Axillary, Musculocutaneous, proximal Radial, distal Radial, Median and Ulnar nerves in 33 babies (age 10 - 60 days) with obstetrical brachial plexus lesions in order to compare the amplitude of compound muscle action potentials (CMAPs). The babies were followed up for six months and the outcome was classified according to muscle power score and functional performance. A CMAP amplitude reduction in any nerve of the injured side superior or equal to 90% of CMAP amplitude of the normal side was related to an unfavorable clinical result at age of six months (p < 0,01). The prognostic accuracy of electroneurography was 91% for the upper trunk, 97% for the middle trunk and 100% for the lower trunk. Our results indicate that electroneurography seems to be a useful tool for very early prognostic assessment of obstetric brachial plexopathies

La paralysie obstétricale du plexus brachial (POPB) est une paralysie du membre supérieur qui survient à la naissance et peut entraîner une déformation de l'articulation et un fonctionnement anormal de l'épaule. Bien que le traitement de la POPB tente de restaurer la fonction de l'épaule, la pathomécanique sous-jacente n'est pas encore clairement comprise. Les modèles computationnels sont efficaces pour fournir de telles informations, mais il n'existe aucun modèle d'articulation de l'épaule pédiatrique pour comprendre la POPB. Ainsi, ce travail de recherche a pour but de construire un framework combinant les avancées dans les domaines de la modélisation statistique de forme (MSF) et de la modélisation musculo-squelettique multi-corps (MCM). Due à l’insuffisance des données dans la cohorte pédiatrique, ce cadre a été mis en place pour l'articulation de l'épaule adulte. Pour cela, la précision de la MSF a été illustrée en prédisant 1) la forme de l'omoplate pré-morbide, et 2) les régions d'insertion musculaire sur l'omoplate et l'humérus. Cette méthode a ensuite été intégrée aux modèles MCM pour l'épaule adulte pour souligner l’importance des modèles spécifique-patient pour l’usage clinique. Pour le second objectif de cette thèse, j'ai développé un modèle MCM pédiatrique du complexe articulaire de l'épaule en utilisant le logiciel OpenSim. Grâce aux approches de cinématique et dynamique inverse, le modèle a permis de déterminer les différences de dynamique articulaires entre le côté sain et le côté pathologique. Les travaux futurs seront axés sur l’extension du travail réalisé pour la population pédiatrique afin de comprendre la pathomécanique de POPB. / Obstetrician Brachial Plexus Palsy (OBPP) is a common birth injury in children leading to shoulder joint deformity and abnormal function. While the management of OBPP disorder focuses on restoring the shoulder joint function, the underlying pathomechanics is not clearly understood yet. Computational models are effective to provide such insights, however, there is no pediatric shoulder joint model to understand the OBPP disorder. Thus, the global aim of this research work was to build a computational framework combining the advances in statistical shape modeling (SSM) and multi-body musculoskeletal modeling (MSKM) domains. Due to a lack of sufficient data in the pediatric cohort, I first developed the framework for adult shoulder joint. For this, I illustrated the accuracy of SSM in predicting 1) missing part of the scapula, and 2) muscle insertion regions on scapula and humerus bones. This method was then integrated with adult shoulder MSKMs to show the differences between generic and subject specific constructs. For the second aim of this thesis, I developed a pediatric MSKM of the shoulder joint complex using OpenSim software. Pediatric MSKM represented scapulothoracic, sternoclavicular, acromioclavicular, and glenohumeral joints with 13 degrees of freedom, and actuated by 52 musculotendon actuators representing 14 shoulder muscles. Using inverse kinematics and inverse dynamics approaches, the model was used to determine the differences in joint kinematics, and joint dynamics between healthy and unhealthy side of a single OBPP subject. Future work is focused on completing the framework on pediatric population and understanding the pathomechanics of OBPP.

Au cours des vingt dernières années, l’anesthésie régionale est devenue, autant en médecine vétérinaire qu’humaine, un outil essentiel à l’élaboration de protocoles analgésiques péri-opératoires. Parmi l’éventail de techniques mises au point en anesthésie canine, le bloc paravertébral du plexus vertébral (PBPB) et sa version modifiée sont d’un grand intérêt pour toute procédure du membre thoracique, dans sa portion proximale. Toutefois, l’essentiel des données publiées à ce jour provient d’études colorimétriques, sans évaluation clinique, et peu d’information est disponible sur les techniques de localisation nerveuse envisageables à ce site. Notre étude visait à décrire une approche échoguidée du PBPB modifié, puis à caractériser ses paramètres pharmacocinétiques et pharmacodynamiques après administration de lidocaïne (LI) ou lidocaïne adrénalinée (LA). Huit chiens ont été inclus dans un protocole prospectif, randomisé, en aveugle et croisé, réparti sur trois périodes. L’impact pharmacodynamique du bloc effectué avec LI ou LA a été évalué régulièrement pour 180 min suivant son exécution. Le traitement à l’adrénaline n’a pas démontré d’impact significatif (P = 0,845) sur la durée du bloc sensitif, tel qu’évalué par un stimulus douloureux mécanique appliqué aux dermatomes ciblés. À l’opposé, l’atteinte proprioceptive évaluée par la démarche a été trouvée prolongée (P = 0,027) et le bloc moteur mesuré par le pic de force verticale (PVF) au trot sur la plaque de force s’est avéré plus marqué (PVF réduit; P = 0,007) sous LA. À l’arrêt comme au trot, le nadir de la courbe PVF-temps a été trouvé retardé (P < 0,005) et la pente ascendante de retour aux valeurs normales adoucie (P = 0,005). Parallèlement aux évaluations cliniques, des échantillons plasmatiques ont été collectés régulièrement afin de quantifier et décrire le devenir pharmacocinétique de la lidocaïne. Parmi les trois élaborés, un modèle bi-compartimental doté d’une double absorption asynchrone d’ordre zéro a finalement été sélectionné et appliqué aux données expérimentales. Sous LA, la Cmax a été trouvée significativement diminuée (P < 0,001), les phases d’absorption prolongées [P < 0,020 (Dur1) et P < 0,001 (Dur2)] et leurs constantes réduites [P = 0,046(k01) et P < 0,001 (k02)], le tout en concordance avec les effets proprioceptifs et moteurs rapportés. Bien que l’extrapolation du dosage soit maintenant théoriquement envisageable à partir du modèle mis en lumière ici, des études supplémentaires sont encore nécessaires afin d’établir un protocole de PBPB d’intérêt clinique. L’analyse sur plaque de force pourrait alors devenir un outil de choix pour évaluer l’efficacité du bloc dans un cadre expérimental. / Over the last decade, regional anaesthesia has become a gold standard for peri-surgical management in veterinary medicine. Among the many techniques developed for analgesia in dogs, the paravertebral brachial plexus block (PBPB) is of great interest when targeting the proximal half of the thoracic limb. Yet, most available data on this technique is based on colorimetric protocols rather than clinical evaluation, and there are very few published results for PBPB execution using nerve location techniques. Through this work, we wished to describe an ultrasound-guided approach of the PBPB and characterize its pharmacokinetic/ pharmacodynamic parameters when executed with either lidocaine alone (LI) or combined to adrenaline (LA). Eight dogs were included in a prospective, randomised, blinded, crossover protocol performed over three distinct periods. Pharmacodynamic impact of LI and LA was compared for 180 minutes after block administration. No significant difference (P = 0.845) was noted between treatments regarding length of the sensitive block, as evaluated regularly through a mechanical painful stimulus applied to selected dermatomes. On the opposite, gait examination showed a longer proprioceptive deficit using LA (P = 0.027). Motor block measured with dynamic force plate analysis showed a lower peak vertical force with LA than LI (P = 0.007). For both dynamic and static evaluations, nadir was clearly delayed (P < 0.005) and the ascending slope back to baseline significantly softened (P = 0.005) in the LA group. Throughout block execution and evaluation, blood samples were collected regularly in order to quantify and describe lidocaine kinetics. Models where developed and compared. A two-compartment model with dual zero-order absorption processes was selected as the best fit for our experimental data. Cmax proved to be significantly reduced with LA (P < 0.001), thus reducing potential toxicity. Absorption phase was prolonged [P < 0.020 (Dur1) and P < 0.001 (Dur2)] and zero-order absorption constant rates lowered [P = 0.046(k01) and P < 0.001 (k02)] following adrenaline addition, in accordance with the previously noted prolonged gait and motor effects. Though dosage extrapolation is now possible using the model developed and tested here, further studies would be needed to establish a PBPB protocol of more clinical interest. Then, force plate analysis could become a key tool for block quality assessment, as both dynamic and static measurements proved to be the reliable ways to collect ground reaction force (GRF) data.

A lesão do plexo braquial é considerada a alteração neural mais grave das extremidades. A principal causa é o trauma de alta energia, especialmente acidentes envolvendo veículos a motor. Por este motivo, as lesões traumáticas do plexo braquial são cada vez mais frequentes. O presente estudo avaliou a acurácia da ressonância magnética (RM) no diagnóstico das lesões traumáticas do plexo braquial no adulto, utilizando o achado intraoperatório como padrão-ouro. Também foi avaliada a acurácia da neurografia pesada em difusão (neurografia DW) em relação à RM convencional e a capacidade de diferenciação dos três tipos de lesão: avulsão, ruptura e lesão em continuidade. Trinta e três pacientes com história e diagnóstico clínico de lesão traumática do plexo braquial foram prospectivamente estudados por RM. Os achados obtidos pela RM sem e com o uso da neurografia DW, e os achados de exame clínico foram comparados com os achados intraoperatórios. A análise estatística foi feita com associação de significância de 5%. Observou-se alta correlação entre a RM com neurografia DW e a cirurgia (rs=0,79), e baixa correlação entre a RM convencional e a cirurgia (rs=0,41). A correlação interobservador foi maior para a RM com neurografia DW (rs = 0,94) do que para a RM sem neurografia DW (rs = 0,75). Os resultados de sensibilidade, acurácia e valor preditivo positivo foram acima de 95% para as RM com e sem neurografia DW no estudo de todo o plexo. As especificidades foram, em geral, maiores para a neurografia DW (p < 0,05). Em relação à diferenciação dos tipos de lesão, a RM com neurografia DW apresentou altas acurácias e sensibilidades no diagnóstico da avulsão/rotura, e alta especificidade no diagnóstico da lesão em continuidade. A acurácia da RM (93,9%) foi significativamente maior que a do exame clínico (76,5%) no diagnóstico das lesões de todo o plexo braquial (p < 0,05). / Brachial plexus injury is considered the most severe neural disorder in the extremities and in general resulting from high-energy trauma in young patients, usually involving motor vehicles. For this reason, traumatic brachial plexus injuries are becoming more frequent. This study evaluated the accuracy of magnetic resonance imaging (MRI) in the diagnosis of traumatic brachial plexus injuries in adults, using surgical findings as the gold standard method. We also evaluated the accuracy of diffusion weighted image neurography (DW neurography) compared to conventional MRI and the ability to differentiate the three types of injuries by MRI: avulsion, rupture and lesion-in-continuity. Thirty-three patients with clinical history and diagnosis of traumatic brachial plexus injury were prospectively studied by MRI. MRI findings (obtained with and without use of DW neurography) and clinical examination were compared with intraoperative findings. The statistical analysis was performed with 5% significance association. There was high correlation between MRI with DW neurography and surgery (rs = 0.79) and low correlation between conventional MRI and surgery (rs = 0.41). The interobserver correlation was higher for MRI with DW neurography (rs = 0.94) than for regular MRI (rs = 0.75). The sensitivities, accuracies and positive predictive values were above 95% for MRI (with and without DW neurography) in the evaluation of the entire plexus. The specificities were generally higher for DW neurography (p < 0.05). Regarding the differentiation between types of lesions, MRI with DW neurography demonstrated high accuracies and sensitivities in the diagnosis of avulsion / rupture and high specificity in the diagnosis of lesion-in-continuity. MRI accuracy (93.9%) was significantly higher than clinical examination (76.5%) in diagnosis of brachial plexus traumatic lesions (p < 0.05).

A lesão do plexo braquial é considerada a alteração neural mais grave das extremidades. A principal causa é o trauma de alta energia, especialmente acidentes envolvendo veículos a motor. Por este motivo, as lesões traumáticas do plexo braquial são cada vez mais frequentes. O presente estudo avaliou a acurácia da ressonância magnética (RM) no diagnóstico das lesões traumáticas do plexo braquial no adulto, utilizando o achado intraoperatório como padrão-ouro. Também foi avaliada a acurácia da neurografia pesada em difusão (neurografia DW) em relação à RM convencional e a capacidade de diferenciação dos três tipos de lesão: avulsão, ruptura e lesão em continuidade. Trinta e três pacientes com história e diagnóstico clínico de lesão traumática do plexo braquial foram prospectivamente estudados por RM. Os achados obtidos pela RM sem e com o uso da neurografia DW, e os achados de exame clínico foram comparados com os achados intraoperatórios. A análise estatística foi feita com associação de significância de 5%. Observou-se alta correlação entre a RM com neurografia DW e a cirurgia (rs=0,79), e baixa correlação entre a RM convencional e a cirurgia (rs=0,41). A correlação interobservador foi maior para a RM com neurografia DW (rs = 0,94) do que para a RM sem neurografia DW (rs = 0,75). Os resultados de sensibilidade, acurácia e valor preditivo positivo foram acima de 95% para as RM com e sem neurografia DW no estudo de todo o plexo. As especificidades foram, em geral, maiores para a neurografia DW (p < 0,05). Em relação à diferenciação dos tipos de lesão, a RM com neurografia DW apresentou altas acurácias e sensibilidades no diagnóstico da avulsão/rotura, e alta especificidade no diagnóstico da lesão em continuidade. A acurácia da RM (93,9%) foi significativamente maior que a do exame clínico (76,5%) no diagnóstico das lesões de todo o plexo braquial (p < 0,05). / Brachial plexus injury is considered the most severe neural disorder in the extremities and in general resulting from high-energy trauma in young patients, usually involving motor vehicles. For this reason, traumatic brachial plexus injuries are becoming more frequent. This study evaluated the accuracy of magnetic resonance imaging (MRI) in the diagnosis of traumatic brachial plexus injuries in adults, using surgical findings as the gold standard method. We also evaluated the accuracy of diffusion weighted image neurography (DW neurography) compared to conventional MRI and the ability to differentiate the three types of injuries by MRI: avulsion, rupture and lesion-in-continuity. Thirty-three patients with clinical history and diagnosis of traumatic brachial plexus injury were prospectively studied by MRI. MRI findings (obtained with and without use of DW neurography) and clinical examination were compared with intraoperative findings. The statistical analysis was performed with 5% significance association. There was high correlation between MRI with DW neurography and surgery (rs = 0.79) and low correlation between conventional MRI and surgery (rs = 0.41). The interobserver correlation was higher for MRI with DW neurography (rs = 0.94) than for regular MRI (rs = 0.75). The sensitivities, accuracies and positive predictive values were above 95% for MRI (with and without DW neurography) in the evaluation of the entire plexus. The specificities were generally higher for DW neurography (p < 0.05). Regarding the differentiation between types of lesions, MRI with DW neurography demonstrated high accuracies and sensitivities in the diagnosis of avulsion / rupture and high specificity in the diagnosis of lesion-in-continuity. MRI accuracy (93.9%) was significantly higher than clinical examination (76.5%) in diagnosis of brachial plexus traumatic lesions (p < 0.05).